Air motor assembly



Oct. 16, 1962 J. D. BROWN AIR MOTOR ASSEMBLY s sheets-sheet 1 FiledMarch 10, 1961 INVENTOR. JAMES D. BROWN BY 22; 4m

A TORNEY Oct. 16, 1962 J. D. BROWN AIR MOTOR'ASSEMBLY 3 Sheets-Sheet 2Filed March 10, 1961 BY J W R m 0 m m V m D 8 0E E M A J 3 WIN I W M mm9 J. D. BROWN AIR MOTOR ASSEMBLY Oct. 16, 1962 3 Sheets-Sheet 3INVENTOR. JAMES 0. BROWN WQJM ATTORNEY Filed March 10, 1961 UnitedStates Patent 3,058,451 MOTOR ASSEMBLY James D. Brown, Salt Lake City,Utah, assignor to The Eimco Corporation, Salt Lake City, Utah, acorporation of Delaware Filed Mar. 10, 1961, Ser. No. 94,826 Claims.(Cl. 121-121) This invention relates generally to fluid driven pistonmotors and in particular to an improved construction of an air motor andair valve assembly.

As is well known, in piston type pneumatic motors, actuating air isadmitted to the top of the piston for the power stroke and is exhaustedas the piston returns to the top of the cylinder.

In a usual construction of such motors, the air valve which supplies andexhausts air in timed sequence is mounted in an associated valvehousing; and the valve itself is driven by the crank shaft of the motor.

It is the primary object of this invention to provide an improved valveand valve housing in combination with a piston type air motor, whichvalve and housing are constructed and assembled in a certain particularmanner to enable improved air flow and consequent increased powerwithout increase in the over-all size of the assembly.

It is a further object to provide such a structure that is simple ofmanufacture and assembly yet has an increased life due to its manner ofconstruction.

In order that the invention may be more readily understood and carriedinto effect, reference is made to the accompanying drawings which areoffered by way of example only and are not to be taken as limiting theinvention the scope of which is defined by the appended claims.

In such drawings:

FIG. 1 is a sectional view of a piston type air motor, valve housing andvalve assembly.

FIG. 2 is an exploded partial view, showing further the relationship anddetails of the various elements of the assembly shown in FIG. 1.

FIG. 3 is a view taken in the plane of line 3-3 of FIG. 2.

FIG. 4 is a view taken in the plane of lines t -4 of FIG. 1, the valvehousing and valve being entirely omitted for purposes of clarity.

FIG. 5 is a view taken in the plane of line 5-5 of FIG. 3.

In the drawings, there is shown an air motor assembly comprisinggenerally a motor housing in which there is suitably mounted acrankshaft 11 to which are afiixed in the usual fashion a plurality ofpiston 12, mounted to reciprocate in cylindrical housings 13. As iscustomary, the pistons are connected to the throw arm of the crankshaftby means of connecting rods 15 which are journalled at one end to thecrankshaft 11 and at the other end to wrist pins 14.

Communicating with the top of each cylinder is an air passage 16 whichcommunicates with the interior of a valve housing 17 afiixed to themotor housing.

The valve housing 17 is a cast unitary structure fitted into a bore 18in one side plate of the motor housing and fixedly connected thereto bymeans of equally spaced bolts 19 which serve to position the valvehousing for proper timing of air flow. Precise positioning of the valvehousing is further insured by means of a dowel pin 21 which is adaptedto fit into any one of the five recesses 22 spaced at 72 intervals aboutthe face of the motor housing in spaced relationship to the bore.

As is best shown in FIG. 2, there is provided a valve body 25 adapted tobe rotatably received in the valve housing and to accommodate air flowin known fashion in proper sequence upon rotation. In this connection,the

3,058,451 Patented Oct. 16, 1962 valve is provided with suitable portssuch as 26, 27, 28 and 29. Of these, ports 27 and 28 are suitable foreither infiow or outflow of air depending upon reverse or forwarddriving of the motor, while port 26 provides the major air exhaustthrough the center of the valve body in known manner.

Annular air passages 31 and 32 are provided in the valve housing tocommunicate with plenum chambers such as 31'. 7

As the valve rotates, incoming air is admitted through one of the firstmentioned passages whence it passes into the communicating air passageleading to the top of the cylindrical section. Upon further rotationexhaust cores come into communication with the air passages and, as thepiston rises in the cylinder, air is forced out through the exhausts. 7

It is the most significant feature of this invention that the valve bodyand housing are each cast as unitary members. The use of such caststructures is enabled by the positive journalling of the valve body atboth ends to rotate Within the housing in fixed spaced relationship tothe interior walls thereof. In this connection, particular attention isdirected to FIG. 3 in which it will be noted that the inner end of thevalve body is provided with a tang 33 which is designed to fit into arecess 34 in the end of the crankshaft (FIG. 4). The tang is offset fromthe center as is the recess in the crankshaft. This insures properassembly of the valve for correct timing as the valve body and housingcan only be assembled to the motor housing when the tang is properlyfitted in the recess. The tank fits into the bearing 36 in the motorhousing with the opposite end edges of the tang in contact with thebearing and thus journalled for rotation, at the same time being heldagainst radial displacement.

At the opposite end of the valve body there is provided a bearing 37fitted into a recess 38 on the outer face of the valve housing and heldin place by means of the outer face or ring 35 serving as a clampsecuring only the outer ring of the bearing in place. The outer face isopen in the center to provide free air discharge from the center of thevalve housing.

The outer bearing serves to mount the valve body rigidly and prevent anyradial movement and also hold it in fixed spaced relationship to theinterior of the valve housing. This is very important considerationbecause it obviates the necessity for a bearing surface between thevalve and housing. This in turn does away with the need for lubricationand, even more important, makes possible completely free communicationbetween the ports in the valve and the cores of the valve housing. Thisis to be distinguished from prior structures which employ a pressed-inbushing extending throughout the length of the valve housing and havingonly intermittent openings providing communication with the air passagesand plenum spaces of the housing. Elimination of this bushing andconsequent interfering structures is made possible by the presentinvention with its combinaiton of casing and unique positive mountingthereof. Obviously, any need to replace worn bushings is alsoeliminated.

In the embodiment shown, the motor is a five cylinder structure and thevalve housing is equipped with spaced mounting lugs 41 so that it may beselectively mounted in any one of five positions without changing thecorrect timing of air flow.

As is usual in structures of the type under discussion, air is admittedthrough port 42 or 43 depending upon whether forward or reverse motionis desired, the air supply being controlled by a suitable valve notshown.

The structure illustrated is adapted to be used with the crankshaft ineither the horizontal position as shown or in vertical position. Inhorizontal use, splash type lubri- D caiton is provided by a splashplate 46 dipping into an oil reservoir.

In vertical use, pressured lubrication is employed and this isaccomplished by lubricant passages 47, 48, 49 and 50 which, when not inuse, can be easily plugged.

It will be seen from the foregoing that the present invention provides astructure which, because of its method of assembly enables the use ofcast construction which in turn provides unobstructed air flows hencegreater efficiency of operation and greatly reduced maintenance.

I claim:

1. In an air motor of the type including a motor and motor housing and avalve housing and valve body for supplying and exhausting air to andfrom the motor in timed sequence; the improved construction comprisingbearing means at opposite ends of said valve body journalling the samefor rotation within said valve housing in predetermined spaced-apartrelationship with the walls thereof, a recess in one end of thecrankshaft and offset from the center line thereof, a tank extendingfrom one end of said valve body and ofiset from its center and adaptedto fit into said recess to thereby fix said valve body in properrelationship to said crankshaft, and a clamp engaging the bearing at theopposite end of said valve body to secure it and said valve body Withinsaid valve housing.

2. Construction according to preceding claim 1 in which the valvehousing has air passage cores cast therein and is free from addedstructure thereby providing unobstructed air passages in said valvehousing.

3. Construction according to preceding claim 2 in which said valve bodyis of unitary cast construction and air passage cores in said valve bodyare free from other structures thereby providing unobstructed airpassage through said cores.

4. A structure according to preceding claim 3 in which an exhaust coreis provided in said valve body axially of said body and communicatesthrough an opening in the outer end of said valve housing, said openingbeing provided in said clamp engaging the bearing in which said valvebody is journalled at said end.

5. A structure according to preceding claim 4 in which said hearing atsaid opposite end of said valve housing is a concentric ring bearing andsaid clamp engages only the outer of said concentric rings.

References Cited in the file of this patent UNITED STATES PATENTS 58,843Lawther et a1 Oct. 16, 1886 2,372,523 Sinclair Mar. 27, 1945 2,945,479Polio July 19, 1960

